var CRC = {};
CRC._auchCRCHi = [
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
];
CRC._auchCRCLo = [
  0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
  0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
  0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
  0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
  0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
  0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
  0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
  0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
  0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
  0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
  0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
  0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
  0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
  0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
  0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
  0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
  0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
  0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
  0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
  0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
  0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
  0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
  0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
  0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
  0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
  0x43, 0x83, 0x41, 0x81, 0x80, 0x40
];

CRC.CRC16 = function(buffer) {
  var hi = 0xff;
  var lo = 0xff;
  for (var i = 0; i < buffer.length; i++) {
    var idx = hi ^ buffer[i];
    hi = (lo ^ CRC._auchCRCHi[idx]);
    lo = CRC._auchCRCLo[idx];
  }
  return CRC.padLeft((hi << 8 | lo).toString(16).toUpperCase(), 4, '0');
};

CRC.isArray = function(arr) {
  return Object.prototype.toString.call(arr) === '[object Array]';
};

CRC.ToCRC16 = function(str) {
  return CRC.CRC16(CRC.isArray(str) ? str : CRC.strToByte(str));
};

CRC.ToModbusCRC16 = function(str) {
  return CRC.CRC16(CRC.isArray(str) ? str : CRC.strToHex(str));
};

CRC.strToByte = function(str) {
  var tmp = str.split(''),
    arr = [];
  for (var i = 0, c = tmp.length; i < c; i++) {
    var j = encodeURI(tmp[i]);
    if (j.length == 1) {
      arr.push(j.charCodeAt());
    } else {
      var b = j.split('%');
      for (var m = 1; m < b.length; m++) {
        arr.push(parseInt('0x' + b[m]));
      }
    }
  }
  return arr;
};

CRC.convertChinese = function(str) {
  var tmp = str.split(''),
    arr = [];
  for (var i = 0, c = tmp.length; i < c; i++) {
    var s = tmp[i].charCodeAt();
    if (s <= 0 || s >= 127) {
      arr.push(s.toString(16));
    } else {
      arr.push(tmp[i]);
    }
  }
  return arr;
};

CRC.filterChinese = function(str) {
  var tmp = str.split(''),
    arr = [];
  for (var i = 0, c = tmp.length; i < c; i++) {
    var s = tmp[i].charCodeAt();
    if (s > 0 && s < 127) {
      arr.push(tmp[i]);
    }
  }
  return arr;
};

CRC.strToHex = function(hex, isFilterChinese) {
  hex = isFilterChinese ? CRC.filterChinese(hex).join('') : CRC.convertChinese(hex).join('');

  //清除所有空格
  hex = hex.replace(/\s/g, "");
  //若字符个数为奇数，补一个空格
  hex += hex.length % 2 != 0 ? " " : "";

  var c = hex.length / 2,
    arr = [];
  for (var i = 0; i < c; i++) {
    arr.push(parseInt(hex.substr(i * 2, 2), 16));
  }
  return arr;
};

CRC.padLeft = function(s, w, pc) {
  if (pc == undefined) {
    pc = '0';
  }
  for (var i = 0, c = w - s.length; i < c; i++) {
    s = pc + s;
  }
  return s;
};
/**
 *
 * 标准CRC16校验码
 * @decimalBytes 输入十进制的字节数组
 * @return  返回uint16的数字
 *
 * demo
 *    const {decimalBytes} = PMQTPTools.transToUTF8('123456789');
 *      let crc = PMQTPTools.crc16(decimalBytes);
 *      hexCRC = PMQTPTools.uint16ToHexString(crc);
 *      console.log(hexCRC); // 29b1
 *
 */
  function CRC16_CCITT(charach) {
    var crc = 0xFFFF;
    var polynomial = 0x1021;
    var i = 0, k = 0, byte_val, bit, c15;

    for (; i < charach.length; i++) {
      byte_val = charach[i].charCodeAt(0);

      for (k = 0; k < 8; k++) {
        bit = ((byte_val >> (7 - k) & 1) == 1);
        c15 = ((crc >> 15 & 1) == 1);
        crc <<= 1;
        if (c15 ^ bit) {
          crc ^= polynomial;
        }
      }
    }
    crc &= 0xffff;

    return crc.toString(16);
};
/**
     *
     * 标准CRC16校验码
     * @decimalBytes 输入十进制的字节数组
     * @return  返回uint16的数字
     *
     * demo
     *    const {decimalBytes} = PMQTPTools.transToUTF8('123456789');
     *      let crc = PMQTPTools.crc16(decimalBytes);
     *      hexCRC = PMQTPTools.uint16ToHexString(crc);
     *      console.log(hexCRC); // 29b1
     *
     */
  function crc16(hexString) {
    var str = _hexStringToString(hexString);
    var crc = 0xFFFF;
    for (var c = 0; c < str.length; c++) {
      crc ^= str.charCodeAt(c) << 8;
      for (var i = 0; i < 8; i++) {
        if (crc & 0x8000)
          crc = (crc << 1) ^ 0x1021;
        else
          crc = crc << 1;
      }
    }
    var crcByte = (crc & 0xFFFF).toString(16).toUpperCase();
    if(crcByte.length==1){
      crcByte='000'+crcByte
    }else if(crcByte.length==2){
      crcByte='00'+crcByte
    }else if(crcByte.length==3){
      crcByte='0'+crcByte
    }
    
    if(crcByte.length==4){
      crcByte=crcByte.substr(2,4)+crcByte.substr(0,2)
    }
  
    return crcByte;
};
function _hexStringToString(inputstr) {
  var hex = inputstr.toString(); //force conversion
  var str = '';
  for (var i = 0; i < hex.length; i += 2)
    str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
  return str;
};

module.exports = {
  ToCRC16: crc16,
}